function handleHeaderRequest(req) {
    appendBefore(req.responseText, "top");
}

ajaxSucceededToLoad = sendRequest("header.html", handleHeaderRequest);
if (!ajaxSucceededToLoad) { // IE prohibits loading local files
      appendThis("<iframe src=\"header.html\" width=600 height=50 marginheight=0 marginwidth=0 frameborder=0 scrolling=\"no\"></iframe>", "logo");
}